A diode array is a type of electronic component that consists of multiple diodes within a single package. This is usually referred to as a semiconductor package and can take a number of different forms. The individual diodes in an array may share a common anode or cathode, or each may be separate. A diode array may also take the form of several different package types, such as a through hole and surface mount. Many diode arrays make use of light emitting diodes (LEDs) or photodiodes to achieve specific purposes, such as printing, the scanning of images, or various visual effects.
Diodes are electronic components that allow current to flow only in one direction. Specialized diodes can either emit light or sense it due to the way that electricity passes through the semiconductor material. All semiconductors can be subject to interference from light, though they are typically coated in special materials to prevent it. Photodiodes can be left uncovered to allow photons to reach the semiconductor and interact with it.
There are many different ways that a diode array can be used. Light emitting diode arrays are often used in flashlights. It is not normally possible to get white light out of an LED unless a three diode array is used. This effect can also be achieved by using a blue LED that has been coated in a colored material, either singly or in an array. LED arrays have also been used to create monochrome three dimensional video game graphics.
Another use for a light emitting diode array is in LED printing. This process is similar to laser printing, in that the light emitting diodes shine on a page prior to a print drum applying ink according to the pattern that was displayed. The main difference is that a single LED array is able to illuminate the entire width of a page at once, so there can be fewer moving parts involved.
Light emitting diodes and photodiodes may also be used in a variety of scanning technologies. Both flatbed and handheld image scanners can use diode arrays. This usually involves illuminating an image with light emitting diodes, after which voltage inputs from photodiode arrays are used to digitize it. Linear photodiode arrays can also be used to digitize x-ray images. This typically involves coating the array in a scintillating material so that the photodiodes will be sensitive to x-rays rather than just normal light.